Fan construction for air-cooled engines



0a. 13, 1942. Q 'AN 2,299,010

FAN CONSTRUCTION FOR AIR-COOLED ENGINES Filed Aug. 15, 1939 I 1NVENTOR.

ATTORNEYS- Pa'tented Oct. 13 1942 S PATENT OFFICE FAN CONSTRUCTION FOR AIR-COOLED ENGINES Carl T. Doman, Geddes, N. Y., assignor to Aircooled Motors Corporation, Syracuse, N. Y., a "corporation of New York Application August 15, 1939, Serial No. 290,276

1 Claim.

This invention relates to centrifugal fans, such as are used to create the air currents for cooling, air-cooled engines, and has for its object a construction by which vibration is prevented or dampened, as torque vibration originating in the crank shaft on which the fan is mounted, or vibrations due to fluctuations in the outside air feeding into the fan, or vibrations created or aggravated by the action of the pulley actuated by the fan hub, which pulley is usually employed to drive a belt which in turn drives accessories for the engine, as the generator.

The invention specifically has for its object a fastening and cushioning means between one of the heads of the fan and the hub of the fan by with a transverse hole 1 for receiving a pulling tool or cross bar.

The heads 2 and 3, as well as the vanes l, are usually formed up of sheet metal, and the vanes 4 are usually formed with tangs ill at their ends extending through slots in the heads 2, 3 and clinched over on the said heads and may be welded thereto. These vanes are oftentimes loosened by the vibration of the fan and being loosened set up more vibration and noise. The joint to be presently described between the head 3 and the flange of the hub avoids loosening of the vanes 4, as well as dampens vibrations.

Figure 1 is a fragmentary elevation of the fan embodying this invention.

Figure 2 is asectional view on line 2--2, Figure 1.

Figure 3 is an enlarged fragmentary sectional view of the fastening and cushioning means between one of the heads, as the discoidal rear head of the fan, and the hub of the fan.

I designates the hub of the fan; 2 the front head; 3 the rear head, and 4 the vanes between the front and rear heads at the outer rim of the fan. The hub l is formed with an annular flange 5 and is also formed with internal means, as a groove 6, by means of which it can be keyed or splined to the crank shaft of the engine. The hub 6 is also formed with an axial extension 1 extending beyond the entrance or front end of the fan and the end of the crank shaft on which the hub is mounted. The end of the crank shaft is indicated by the line C. A pulley 8 is mounted on the extension I for driving, by means of a belt, mechanism accessory to the engine, as the generator, etc. The head 2 is annular in form and confines the air entrance 9 of the fan. The head 3 is discoidal and is secured to the hub, as will be presently described.

For the purpose of facilitating the removal of The flange 5 is provided with an annular series of openings II. The inner margin of the head 3-laps the portion of the flange provided with the openings and seats at l2 on an annular shoulder provided on the'flange 5.

l3 designates the fastening members, which are usually rivets, extending axially through the openings II, and H a bushing of compressible, expansible, resilient material, as rubber, encircling the intermediate portion of the rivet l3 and coacting with the walls of the openings ll, these bushings being under axial and radial compression, due to being compressed axially by the fastening members l3. Each intermediate portion of the rivet l3, which the bushing encircles, is of larger diameter than the adjacent portion of the rivet forming grooves l5, l6 into which respectively the inner margin of the head 3 extends, as at H, and the inner margin of an abutment or washer l8 seats. The margin at IT is compressed between the head IQ of the rivet and the opposing wall of the groove IS. The washer I8 is. compressed by the head 20 of the rivet against the opposing wall of the groove l6, this opposing wall constituting an annular shoulder 2|. The shoulder 2| is located out of the opening I l and the bushing I4 is normally of greater axial length than the intermediate portion of the rivet l3, so that when the washer or abutment I8 is compressed by the forming of the rivet head 20, the bushing I4 is compressed axially and caused to expand radially against the wall of the opening II and against the periphery of the intermediate portion l3, and this compression is limited by the shoulder 2|. The shoulder 2| is so located as to provide a clearance at 22 between the washer and the face around the opposing end of the opening H. Thus, each fastening member or rivet is cushioned by the bushing whichis under compression and is also free to tilt in a circumferential direction out of parallelism with the fan from the shaft, the extension is formed theaxis of the fan, and due to this action, vi-

ing in the flange being of greater diameter than 10 that in the head, a fastening member extending axially through the alined openings and formed with a shoulder thrusting against the margin of the wall around the opening in the head, an axially compressible and radially expansible resil- 15 ient bushing around the fastening member within the opening in the flange, abutting at one end against the head and extending at its other end out of the opening in the flange, an abutment at the end 01 the fastening member opposite to that attached to the head, and located outside of the opening in the flange, the fastening member having a shoulder for limiting the movement of the abutment toward the flange and holding it spaced from the wall of the flange around the opening therein, the abutment thrusting against the end or the bushing outside or the opening in the flange, and means for compressing the abutment against the end of the bushing.

CARL T. DOMAN. 

